In a survey of \( 220 \) students of a higher secondary school, it was found that at least \( 125 \) and at most \( 130 \) students studied Mathematics; at least \( 85 \) and at most \( 95 \) studied Physics; at least \( 75 \) and at most \( 90 \) studied Chemistry; \( 30 \) studied both Physics and Chemistry; \( 50 \) studied both Chemistry and Mathematics; \( 40 \) studied both Mathematics and Physics and \( 10 \) studied none of these subjects. Let \( m \) and \( n \) respectively be the least and the most number of students who studied all the three subjects. Then \( m+n \) is equal to \( \_\_\_\_\_\_\_\_\_\_ \).
